Surface operated single tube pump

ABSTRACT

This specification discloses a surface operated single tube pump intended for the raising of oil from the bottom of deep wells, including a small diameter well casing. The pump, considered in its entirety, comprises an air motor located at the ground surface, a tube of a diameter less than that of the well casing, the upper end of which is connected to the air motor, and a bottom pumping unit which is immersed in the oil at the bottom of the well and which comprises a piston slidable in the lower end of a cylinder, a tubular plunger having its upper end connected to said piston with a one-way check valve in the piston controlling the flow of liquid from the plunger through the piston, a spring abutment extending into the bore of the tube below the piston and an expansion coil spring between said abutment and the piston, and a one-way check valve mounted on the lower end of the cylinder for controlling flow of oil from the reservoir into the tube. A valve for bleeding air is mounted on the lower end of the tubular plunger.

[ Apr. 16, 1974 SURFACE OPERATED SINGLE TUBE PUMP [57] ABSTRACT lnvemoflArthur Bentley, BOX This specification discloses a surface operatedsingle Boeme, 78006 tube pump intended for the raising of oil from thebot- May 26, 1972 tom of deep wells, including a small diameter wellcasing. The pump, considered in its entirety, comprises an air motorlocated at the ground surface, a tube of a diameter less than that ofthe well casing, the upper 417/402, 91/229 166/685 end of which isconnected to the air motor, and a bot- F04b 17/00, F041) 3 5 /02 tompumping unit which is immersed in the oil at the 417/401, 166/685;bottom of the well and which comprises a piston slid- 91/229 222 able inthe lower end of a cylinder, a tubular plunger having its upper endconnected to said piston with a References Cited one-way check valve inthe piston controlling the flow of liquid from the plunger through thepiston, a spring UNITED STATES PATENTS abutment extending into the boreof the tube below United States Patent Bentley 22 Filed:

21 Appl. No.: 257,146

51 Int.

[58] Field of Search 2 Claims, 9 Drawing Figures 29 92 9 A \\\\i. O2 2O20 P MH 2 4 2 4 WE 71 V H. .w l m l S91 r. 4 m N E T "m m T s A I m C mmb U n. e o P W, R u" u a P mr. mm m A.m.m eA Nut. .8 33 h ..e t R nu Sn" r r. R 0 new m BB mo io S tt o kn aa 0 mvmcr. T 88 h aaauu QQ wmPLBZT E C T F 28726 A65 !r 40645 55 H60 wgwgg M wyuwwwwm m 1 Il x E X607i]. R96 9 2578 044 y q ,F mm fi 67277 4 d 80074 2 .m o 31 7 HSH 2 322PA SURFACE OPERATED SINGLE TUBE PUMP The present invention relates todeep well pumps which are operated from the surface, and is concernedprimarily with a pump of this type which includes a bottom of wellpumping unit which is operated by pressure of the liquid being pumpedwhich is generated in a sin gle tube that extends from an air motor atthe surface to the bottom of the well unit and which tube also performsthe function of conducting the liquid being pumped to the surface.

BACKGROUND OF THE INVENTION At the present time, deep well pumps of thegeneral nature with which the present invention is concerned are wellknown. Such pumps ordinarily include a pumping unit which is located atthe bottom of the well and a motor or comparable actuating device at thesurface which operates the pump. In most of these known devices, atleast two tubes in addition to the well casing are required. One ofthese tubes delivers liquid under pressure to the pumping unit foractuation thereof, while the liquid being pumped is raised in the othertube. The necessity for two tubes is an obvious disadvantage because itrequires a well casing having a bore of sufficient diameter toaccommodate the tubes.

In most of the pumping units which are installed at the bottom of thewell, a piston is reciprocally mounted in a cylinder and is moved inboth directions by a pressure medium. This results in a complex pumpingmechamsm.

OBJECTS OF THE INVENTION With the foregoing conditions in mind, thepresent invention has in view the following objectives:

1. To provide a surface operated deep well pump which includes ascharacteristic and essential elements a bottom of well pumping unitwhich is mounted on the lower end of a small diameter tube which extendsupwardly through a small diameter well casing to a motor at the topwhich generates pressure on the liquid in the tube to operate the pumpand which tube also conveys the liquid being pumped to the surface.

2. To provide, in a pump of the character aforesaid, a bottom of wellpumping unit which includes a piston reciprocal in the lower end portionof a cylinder a small diameter plunger depending from the piston andspring means for moving the piston upwardly when pressure on the liquidin the tube is relieved.

3. To provide, in a pump of the type noted, a bottom of well unit whichincludes a one-way check valve for controlling the flow of liquid fromthe tubular plunger through the piston and into the tube.

4. To provide, in the pump of the character described, a one-way checkvalve which is mounted on the lower end of a cylinder and which controlsthe flow of liquid from the reservoir at the bottom of the well into thecylinder.

5. Toprovide, in a pump of the character aforesaid, an air bleed whichis mounted on the lower end of the tubular plunger.

6. To provide, in a pump of the type noted, a new and improved air motorwhich is located at the ground surface and which is effective to createpressure on the liquid in the tube and which also controls the upwardflow of the liquid being pumped.

Various other more detailed objects and advantages of the invention suchas arise in connection with carrying out the above ideas in a practicalembodiment will, in part, become apparent, and, in part, be hereafterstated as the description of the invention proceeds.

SUMMARY OF THE INVENTION A tube of a diameter which permits of itsinsertion in the well casing has one end connected to the powercylinder. Mounted on the lower end of this tube is a bottom of wellpumping unit comprising a piston reciprocal in a cylinder, a tubularplunger of a diameter smaller than that of the piston having its upperend connected to the piston with a one-way check valve in the pistoncontrolling flow of the liquid from the plunger into the tube. Extendinginto the bore of the tube below the piston is an abutment. An expansioncoil spring is interposed between the abutment and the piston and iseffective after being compressed by downward movement of the pistonunder the influence of pressure of liquid in the tube to move the pistonupwardly when this pressure is relieved. Mounted on the lower end of thecylinder which is immersed in the oil reservoir at the bottom of thewell is a one-way check valve which controls the flow of oil from thereservoir into the tube. An air bleed valve is also mounted on the lowerend of the tubular plunger.

For a full and more completeunderstan'ding of the invention, referencemay'be had to the following description and the accompanying drawingswherein:

FIG. 1 is a side view showing the groundin section, a well casing brokenaway, an air motor at the ground surface and a bottom of well pumpingunit diagrammatically;

FIG. 2 is a perspective illustrating the air motor in section;

FIG. 3 is a detailed section on an enlarged scale illustrating oneposition of a valve in the air motor;

FIG. 4 is a detailed section similar to FIG. 3, depicting anotherposition of the valve in the air motor piston;

FIG. 5 is a perspective of the bottom of well pumping unit as shown insection;

FIG. 6 is a detailed section on an enlarged scale of the check valveassembly at the upper end of the tubular plunger of the unit of FIG. 5;

FIG. 7 is an enlarged detailed section of the check valve assembly atthe bottom of the pump cylinder;

FIG. 8 is a perspective illustrating the elements of the bleed valve inexploded relation;

FIG. 9 is a perspective of a modification illustrating a mechanicaldevice for reciprocating the power piston in the power cylinder.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,wherein like reference characters denote corresponding parts, and firstmore particularly to FIG. 1, a piece of ground is designated andpresents an upper or ground surface 11. It includes a lower portion overoil sands 12 in which an oil reservoir 13 is formed. Extending betweenreservoir 13 and ground surface 1] is a well casing 14 which is of smalldiameter as compared to such casings heretofore employed having a borewith a diameter in the order of two inches. Mounted on ground surface 11over the upper end of well casing 14 is an air motor identified in itsentirety at 15. Extending through well casing 14 is a tube 16 whichordinarily will have the property of flexibility to the degree whichpermits it to be wound on a drum. Mounted on the lower end of tube 16 isa bottom of well pumping unit designated generally 17 and which isillustrated in FIG. 5.

Referring now to FIG. 2, a power cylinder is designated 18. One end ofcylinder 18 is provided with a flange 19 which is used in attaching theupper end of tube 16 thereto. Cylinder 18 is formed with a lateral port20 and mounted on cylinder 18 is a reservoir 21 which receives andcontains the oil being pumped. Port 20 communicates with bore 22 ofcylinder 18 and reservoir 21. Mounted on the other end of power cylinder18 is a disc-like plate 23. A power piston 24 is reciprocal in bore 22,with a seal 25 being provided where piston 24 passes through an openingin plate 23. Power cylinder 18 is also providedwith a bleed port 26.

Mounted on plate 23 is a motor cylinder 27, and on the outer end of thelatter is a circular head 28. Bolts 29 extend between plate 23 and head28 and maintain the assembled relation of cylinder 27 therebetween.

An air piston 30 reciprocates in cylinder 27 with rings 31 providing aseal therebetween. Piston 30 is mounted on a piston rod 32 which passesthrough an opening 33 in head 28 and its outer end is received in apositioning tube 34, the function of which will be later described. Head28 is provided with an air inlet opening 35 which communicates with afitting 36 to which an air tube 37 is connected. Air tube 37 isconnected to an appropriate source of air under pressure, such as acompressor.

Referring now more particularly to FIG. 3, piston 30 is shown as havingopposed faces 38 and 39. Extending between faces 38 and 39 is a passage40 of circular cross-section with a counterbore 41 at the face 38 and asecond counterbore 42 at the face 39.

As shown more clearly in FIG. 2, piston rod 32 has a longitudinal bore43 which is opened at the outer end of the piston rod and whichterminates at its inner end in a lateral passage 44 which opens ontopassage 40.

A sliding valve is referred to in its entirety by the referencecharacter 45, as depicted in FIGS. 3 and 4. It is of spool shape,presenting a central cylindrical main body portion 46 and end flanges 47and 48. Body portion 46 is formed with an annular groove 49, the bottomof which is formed with openings 50 which communicate with a bore 51 ofsaid body portion 46 in one position of the valve as shown in FIG. 3.Bore 51 is enlarged at each end to provide counterbores 52 and 53. Anexpansion coil spring 54 is received in counterbore 52, and anotherexpansion coil spring 55 in counterbore 53.

Opening onto face 39 is an arm 56 of an elbow passage, the other arm 57of which communicates with bore 51 by way of groove 49, in the positiondepicted in FIG. 4, which shows the valve 45 as shifted to the right,speaking with reference to the showing of the drawing.

Referring now to FIG. 3, a spring abutment 58 is shown as mounted on theinnerface of plate 23 by a screw 59 which may be rotated to adjust theposition of abutment 58 relative to plate 23. The outer end of spring 54is adapted to engage abutment 58 as the valve 45 approaches its limit ofmovement in the direction of plate 23. In order for this to take place,it is necessary that piston 30 be in the angular position which willcause the end of spring 54 to engage abutment 58. To insure of this,that portion of piston rod 32 which is received in tube 34 carries a pin60 which slides in a groove 61 (FIG. 2). Thus, relative rotation ofpiston 30 and cylinder 27 is inhibited.

In describing the operation of air motor 15, the space between piston 30and plate 23 will be referred to as 62 and the space between piston 30and head 28 as 63. With the valve 45 in the position depicted in FIGS. 2and 3, air under pressure enters the inlet 35 and is effective on face39 of piston 30. In this position, communication through the elbowpassages 56 and 57 is prevented because the main body portion 46 ofvalve 45 closes the inner end of elbow arm 47. However, in this sameposition, the inner end of lateral passage 44 communicates throughgroove 49 and openings 50 to the space 62. Thus, pressure of air inspace 63 moves piston 30 towards plate 23, reducing the size of space62. This occurs because air from space 62 is exhausted throughcounterbore 52, bore 51, openings 50, groove 49 lateral passage 44 andbore 43 to the exterior of the cylinder. During this movement, powerpiston 24 is first moved to close port 20 and then apply pressure to theoil in tube 16.

When the outer end of spring 54 engages abutment 58, valve 45 is shiftedfrom the position shown in 53 to that depicted in FIG. 4. In the latterposition, the socalled exhaust passage 44 is closed by the body portion46 of valve 45 and the arm 57 of the elbow passage is open. Thus, airpasses from the space 63 to the space 62 and the pressures on the pistonfaces 38 and 39 are equalized or balanced. However, as the face 38 is ofgreater area than the face 39, the total pressure of air in space 62 onface 38 is greater than the total pressure on face 39 and the piston 30is moved towards the head 28 until spring 55 engages head 28 to cause ashifting of the valve back into the positions of FIG. 2 and 3. Duringthis so-called return stroke, power piston 24 is moved past the port 20to open the latter and permit oil to flow from the tube 16 into thereservoir 21 under the influence of the bottom of the well pumping unit17.

Referring now to FIG. 5, the bottom of well pumping unit 17 is shown asmounted on the lower end of the tube 16. This unit includes a pumpcylinder 6, which has a bore 64. Slidable in bore 64 is a pump piston 65having a threaded socket 66 at one end which receives a fitting 67formed with a central passage 68. The other or lower end of piston 65 isformed with another threaded socket 69 which receives a fitting 70 thatanchors the upper end of a tubular plunger 71 to piston 65.

Opening onto socket 66 is a valve chamber 72 terminatingat its lower endin a tapered seat. A ball valve 73 is loosely received in chamber 72 andis movable into open position by upward pressure of oil from plunger 71.Fitting 67 is formed at its lower end with two radial grooves 74 whichcommunicate between chamber 72 and passage 68 where ball 83 is itsuppermost position engaging the lower end of fitting 67.

Ball valve 73 and the structure associated therewith constitutes aone-way check valve. Under many conditions one such check valve at theupper end of plunger 71 will be satisfactory. However, to assure ofbetter results, two such check valves are provided at this point. Thus,piston 65 has an inwardly extending flange 75 defining a restricted bore76 which opens onto the tapered bottom of chamber 72 at its upper endand onto a lower valve chamber 77 terminating in a conical seat,

the lower end of which communicates with a passage 78 in fitting 70.Tubular plunger 71 communicates with passage 78.

Piston 65 is formed with a pair of radial grooves 79 which open ontochamber 77 with their inner ends opening onto bore 76. Thus, whenasecond ball valve 80 is moved upwardly by fluid pressure intoengagement with flange 75, oil will flow from chamber 77 into bore 76.

A packing 81 is interposed between fitting 70 and pump cylinder 6 belowpiston 65 and movesywith the piston. A spring abutment 82 extendsinwardly from pump cylinder 6 and is engaged by the lower end of anexpansion coil spring 83. The upper end of spring 83 engages pac king81and serves a dual function. Its main purpose is to move piston 65 andplunger 71 upwardly after it has been compressed, but it also performsthe auxilliary function of tending to expand packing 81 against theinner surface of pump cylinder 6.

While only a single spring 83 is disclosed in FIG. 5, it will beunderstood that additional springs may be provided in alignment alongpump cylinder 6 to provide a required degree of force.

A cylinder member 9 has externally threaded end portions separated by anannular flange 8. One of these end portions is screwed into the lowerend of pump cylinder 6, while the other end portion is threaded into theupper end of pump closure 7.

Formed on pump closure 7 at its lower end is an upwardly projectingannulus 84 presenting a restricted passage 85. Below annulus 84, closure7 is interally threaded at 86 to provide means for attaching a screen orfilter thereto. Passage 85 opens onto a valve chamber 5, the lower endof which is conical. Chamber 5 terminates at an annular shoulder 87formed with two radial grooves 88. A plug 89 is fitted in a socket 90 inthe lower end of closure 7 and cooperates with chamber 86 -in looselyconfining a ball valve 90 to provide a oneway check valve.

While a single check valve for controlling the flow of oil from theunderground reservoir into the lower end of closure 7 might be adequateunder many conditions, a double check valve atthis site is disclosed.Thus, plug 89 has a restricted bore 91 extending from the lower face ofplug 89 to a conical seat formed as the lower end of a valve chamber 92.The upper face of plug 89 is formed with a pair of radial grooves 93.Plug 89 is secured in position by a cup-shaped nut 94 having a centralpassage 95. An upper ball valve 96 is loosely held in chamber 92 by nut94.

The wall defining tubular plunger 71 is externally threaded. Screwedonto end portion 97 is a sleeve 98 which is slidably received in theupper extension of member 9. The lower end of sleeve 98 carries anendwall formed with a central opening in cooperating rela' tion to theupper end of passage 95 and terminating at a valve member receiving aball valve 99.

A valve block 100 is interposed between the end wall of sleeve 98 andthe end portion 97 of plunger 71. Block 100 is also formed with a valvechamber which receives another ball valve 101. Ball valves 99 and 101,together with the chambers in which they are received, constitute ableed valve assembly which rids the inter ior of plunger 71 of air.

OPERATION The pump is first primed by filling tube 16 withoil. This maybe accompanied by withdrawing power piston 24 to leave port 20 open andintroducing as much oil as is required into reservoir 21. On its powerstroke, piston 24 first closes port 20 and then builds up pressure onthe oil in tube 16.

This pressure is effective on the upper end of piston 65 of the bottomof well unit 17 to move piston 65 downwardly. This movement causes oilwhich has collected in the lower end of tube 16 to enter plunger 71 pastthe bleed valves at the lower end thereof. At the same time, spring 83is compressed. Oil in plunger 71 will be under pressure as the lattermoves downwardly to open valves 73 and and admit oil to theupper side ofpiston 65.

It is noted that the cross-sectional area of passage 68 is much lessthan the area on the underside of piston 65 on which the pressure ofliquid below piston 65 is effective. This underside piston surfacecomprises the shoulder at the lower end of the head of plunger 71 andthe lower surface of packing 81. With downward pressure applied to thecolumn of liquid in pump cylinder 6, piston 65 is moved downwardly tobuild up pressure on the liquid below piston 65. This liquid enters bore78 of plunger 71 and is forced upwardly past check valves 80 and 73 andthrough the passage 68 to the upper side of piston 65 where it joins thecolumn of liquid in bore 64. To insure that this action takes place, thedifference in the exposed cross-sectional areas of the upper and lowersurfaces of check valve 73 cannot be greater than the difference of thelower effective areas of pistons 65 and 98.

When piston 24 makes its return stroke, pressure on the column of oil intube 16 is relieved and port 20 opens. Spring 83 is now effective tomove pump piston 65 upwardly which imparts upward movement to the columnof oil because any tendency of this oil to flow back past the valves 73and 80 is prevented because such a tendency closes these valves.

Upward movement of piston 65 also creates a vacuum condition in pumpcylinder 6 below the piston.

This condition causes oil to flow into the space above closure 7 fromsands 12 because valves and 96 will move to open position to permit suchflow. They are moved to closed position on downward movement of piston65.

THE MODIFICATION While the air motor 15 is believed to be the preferreddevice for reciprocating power piston 24, it is possible to use a purelymechanical device for this purpose.

FIG. 9 illustrates such a device in its simpliest form. Thus, a lever102 is pivoted at 103 on a support 104 and one end is pivotallyconnected at 105 to a push-pull rod 106, which is, in turn, connected toone end of power piston 24.

While preferred specific embodiments are herein disclosed, it is to beclearly understood that the invention is not to be limited to the exactconstructions, mechanisms and devices illustrated and described becausevarious modifications of these details may be provided in putting theinvention into practice.

What is claimed is:

1. In a surface operated deep well pump intended for use with a wellcasing of small diameter:

a. a power cylinder having a bore at said surface;

b. a power piston reciprocal in said bore;

c. means for reciprocating said power piston;

d. a reservoir at said surface and connecting with a port in said powercylinder;

e. a tube of a diameter less than that of said casing and receivedtherein, said tube being connected at one end to said power cylinder andextending substantially to the bottom of said casing, and

f. a bottom of well pumping unit mounted on the other end of said tube,said unit comprisingiz i. a pump cylinder connecting with said tube,

ii. a pump piston reciprocal in said pump cylinder,

iii. a tubular plunger having upper and lower ends, with the upper endfixedly secured to said pump piston and said plunger depending from saidpump piston,

iv. a one-way check valve in said pump piston controlling the flow ofliquid through said pump piston and permitting flow of liquid from saidplunger through said pump piston,

v. an inwardly extending abutment in said pump cylinder,

vi. a compression spring interposed between said pump piston and saidabutment,

vii. a sleeve fixedly secured to the lower end of said plunger, insliding engagement with an inner surface of said pump cylinder andconstituting a seal closing off the lower end of the space between saidpump cylinder and said plunger,

viii. a check valve at the lower end of said pump cylinder and spacedfrom the lower end of said plunger controlling the flow of liquidthereinto, and

ix. an air bleed at the lower end of said plunger in the form FF 5'asemiyefimam. m

2. The surface operated deep well pump of claim 1 in which the air bleedat the lower end of the plunger comprises a pair of aligned one-waycheck valves.

1. In a surface operated deep well pump intended for use with a wellcasing of small diameter: a. a power cylinder having a bore at saidsurface; b. a power piston reciprocal in said bore; c. means forreciprocating said power piston; d. a reservoir at said surface andconnecting with a port in said power cylinder; e. a tube of a diameterless than that of said casing and received therein, said tube beingconnected at one end to said power cylinder and extending substantiallyto the bottom of said casing, and f. a bottom of well pumping unitmounting on the other end of said tube, said unit comprising: i. a pumpcylinder connecting with said tube, ii. a pump piston reciprocal in saidpump cylinder, iii. a tubular plunger having upper and lower ends, withthe upper end fixedly secured to said pump piston and said plungerdepending from said pump piston, iv. a one-way check valve in said pumppiston controlling the flow of liquid through said pump piston andpermitting flow of liquid from said plunger through said pump piston, v.an inwardly extending abutment in said pump cylinder, vi. a compressionspring interposed between said pump piston and said abutment, vii. asleeve fixedly secured to the lower end of said plunger, in slidingengagement with an inner surface of said pump cylinder and constitutinga seal closing off the lower end of the space between said pump cylinderand said plunger, viii. a check valve at the lower end of said pumpcylinder and spaced from the lower end of said plunger controlling theflow of liquid thereinto, and xi. an air bleed at the lower end of saidplunger in the form of a one-way check valve.
 2. The surface operateddeep well pump of claim 1 in which the air bleed at the lower end of theplunger comprises a pair of aligned one-way check valves.